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CVE-2021-47492— mm, thp: bail out early in collapse_file for writeback page

AI Predicted 5.5 Difficulty: Moderate EPSS 0.21% · P11

Affected Version Matrix 8

VendorProductVersion RangeStatus
LinuxLinux99cb0dbd47a15d395bf3faa78dc122bc5efe3fc0< 69a7fa5cb0de06c8956b040f19a7248c8c8308caaffected
99cb0dbd47a15d395bf3faa78dc122bc5efe3fc0< 5e669d8ab30ab61dec3c36e27b4711f07611e6fcaffected
99cb0dbd47a15d395bf3faa78dc122bc5efe3fc0< 74c42e1baacf206338b1dd6b6199ac964512b5bbaffected
5.4affected
< 5.4unaffected
5.10.77≤ 5.10.*unaffected
5.14.16≤ 5.14.*unaffected
5.15≤ *unaffected
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I. Basic Information for CVE-2021-47492

Vulnerability Information
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Vulnerability Title
mm, thp: bail out early in collapse_file for writeback page
Source: NVD (National Vulnerability Database)
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: mm, thp: bail out early in collapse_file for writeback page Currently collapse_file does not explicitly check PG_writeback, instead, page_has_private and try_to_release_page are used to filter writeback pages. This does not work for xfs with blocksize equal to or larger than pagesize, because in such case xfs has no page->private. This makes collapse_file bail out early for writeback page. Otherwise, xfs end_page_writeback will panic as follows. page:fffffe00201bcc80 refcount:0 mapcount:0 mapping:ffff0003f88c86a8 index:0x0 pfn:0x84ef32 aops:xfs_address_space_operations [xfs] ino:30000b7 dentry name:"libtest.so" flags: 0x57fffe0000008027(locked|referenced|uptodate|active|writeback) raw: 57fffe0000008027 ffff80001b48bc28 ffff80001b48bc28 ffff0003f88c86a8 raw: 0000000000000000 0000000000000000 00000000ffffffff ffff0000c3e9a000 page dumped because: VM_BUG_ON_PAGE(((unsigned int) page_ref_count(page) + 127u <= 127u)) page->mem_cgroup:ffff0000c3e9a000 ------------[ cut here ]------------ kernel BUG at include/linux/mm.h:1212! Internal error: Oops - BUG: 0 [#1] SMP Modules linked in: BUG: Bad page state in process khugepaged pfn:84ef32 xfs(E) page:fffffe00201bcc80 refcount:0 mapcount:0 mapping:0 index:0x0 pfn:0x84ef32 libcrc32c(E) rfkill(E) aes_ce_blk(E) crypto_simd(E) ... CPU: 25 PID: 0 Comm: swapper/25 Kdump: loaded Tainted: ... pstate: 60400005 (nZCv daif +PAN -UAO -TCO BTYPE=--) Call trace: end_page_writeback+0x1c0/0x214 iomap_finish_page_writeback+0x13c/0x204 iomap_finish_ioend+0xe8/0x19c iomap_writepage_end_bio+0x38/0x50 bio_endio+0x168/0x1ec blk_update_request+0x278/0x3f0 blk_mq_end_request+0x34/0x15c virtblk_request_done+0x38/0x74 [virtio_blk] blk_done_softirq+0xc4/0x110 __do_softirq+0x128/0x38c __irq_exit_rcu+0x118/0x150 irq_exit+0x1c/0x30 __handle_domain_irq+0x8c/0xf0 gic_handle_irq+0x84/0x108 el1_irq+0xcc/0x180 arch_cpu_idle+0x18/0x40 default_idle_call+0x4c/0x1a0 cpuidle_idle_call+0x168/0x1e0 do_idle+0xb4/0x104 cpu_startup_entry+0x30/0x9c secondary_start_kernel+0x104/0x180 Code: d4210000 b0006161 910c8021 94013f4d (d4210000) ---[ end trace 4a88c6a074082f8c ]--- Kernel panic - not syncing: Oops - BUG: Fatal exception in interrupt
Source: NVD (National Vulnerability Database)
CVSS Information
N/A
Source: NVD (National Vulnerability Database)
Vulnerability Type
N/A
Source: NVD (National Vulnerability Database)
Vulnerability Title
Linux kernel 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Linux kernel是美国Linux基金会的开源操作系统Linux所使用的内核。 Linux kernel存在安全漏洞。攻击者利用该漏洞导致内核恐慌。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

VendorProductAffected VersionsCPESubscribe
LinuxLinux 99cb0dbd47a15d395bf3faa78dc122bc5efe3fc0 ~ 69a7fa5cb0de06c8956b040f19a7248c8c8308ca -
LinuxLinux 5.4 -

II. Public POCs for CVE-2021-47492

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III. Intelligence Information for CVE-2021-47492

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Other References for CVE-2021-47492 (3)

Same Patch Batch · Linux · 2024-05-22 · 63 CVEs total

CVE-2021-47476comedi: ni_usb6501: fix NULL-deref in command paths
CVE-2021-47493ocfs2: fix race between searching chunks and release journal_head from buffer_head
CVE-2021-47495usbnet: sanity check for maxpacket
CVE-2021-47496net/tls: Fix flipped sign in tls_err_abort() calls
CVE-2021-47494cfg80211: fix management registrations locking
CVE-2021-47482net: batman-adv: fix error handling
CVE-2021-47480scsi: core: Put LLD module refcnt after SCSI device is released
CVE-2021-47478isofs: Fix out of bound access for corrupted isofs image
CVE-2021-47479staging: rtl8712: fix use-after-free in rtl8712_dl_fw
CVE-2021-47477comedi: dt9812: fix DMA buffers on stack
CVE-2021-47481RDMA/mlx5: Initialize the ODP xarray when creating an ODP MR
CVE-2021-47475comedi: vmk80xx: fix transfer-buffer overflows
CVE-2021-47474comedi: vmk80xx: fix bulk-buffer overflow
CVE-2021-47473scsi: qla2xxx: Fix a memory leak in an error path of qla2x00_process_els()
CVE-2021-47471drm: mxsfb: Fix NULL pointer dereference crash on unload
CVE-2021-47470mm, slub: fix potential use-after-free in slab_debugfs_fops
CVE-2021-47468isdn: mISDN: Fix sleeping function called from invalid context
CVE-2021-47467kunit: fix reference count leak in kfree_at_end
CVE-2021-47466mm, slub: fix potential memoryleak in kmem_cache_open()
CVE-2021-47465KVM: PPC: Book3S HV: Fix stack handling in idle_kvm_start_guest()

Showing top 20 of 63 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

V. Comments for CVE-2021-47492

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